Sweet Potato Curry

peal off husk of sweet potato and cut the same into small pieces. put some oil in a frying pan and when the oil is heated add mustard and the same bursts. boil sweet potato in some water. when it half-baked, add the pieces of onions, cumin seed powder, salt and pungent powder and fry the same in the earlier pan well. after sweet potato and onion are duly fryed, keep the frying pan down